Stairways preferably have risers having a lower end coupled to a rear of a tread, and having an upper end coupled to a front of the next higher tread in the stairway. However, it is still common to find stairways, such as those outside or leading into a basement, which do not include risers. Such riserless stairways can lead to small objects possibly passing through the opening between adjacent treads. More specifically, a small animal such as a pet or even a small child or infant could accidentally fall through the opening and injure itself.
It is therefore a general object of the present invention to provide a stair riser which can be adjusted in height so as to be installed on new or previously built riserless stairways requiring risers of various heights.